Dental Disease in Rabbits: A Simple Overview

by Dana Krempels, Ph.D.

Even if your rabbit has perfectly aligned incisors (front teeth), it
is wise for you to ask your rabbit-experienced veterinarian to do
regular dental checkups as part of your bunny's wellness exam.
Undetected dental problems in rabbits are a major cause of more
serious illnesses which develop due to the pain and stress of sore
teeth and jaw.

Healthy Rabbit Teeth

Rabbits are hypsodonts, meaning their teeth grow continually,
throughout life. In a normal rabbit, the teeth are aligned so that
the teeth wear against each other as the rabbit chews. This maintains even,
relatively flat surfaces (with some sharp edges on top) on the molars
and relatively short, chisel-shaped incisors. The incisors are used
only for cutting the food into manageable pieces. The molars do the
grinding into fine "mash" that is swallowed and sent
down the GI tract for further processing.

Dental Disease

Dental malocclusion in rabbits is not uncommon, especially in the
short-faced breeds produced via generation upon
generation of inbreeding. This often causes harmful, recessive genetic traits to be expressed, and one of these is misalignment of the teeth because of abnormal bone structure in the skull.

Because it is primarily the wearing of the teeth (incisors
and molars) against each other--not against items being chewed--that maintains their
normal length and shape, neither chew toys nor hard
foods will
cure this problem. In many cases, a veterinarian will need to anesthetize the bunny to gain access to the spurs with tools designed specifically to cut off spurs and smooth the teeth.

Incisor Malocclusion

If the teeth do not line up correctly, incisors quickly overgrow and
can become unmanageable "tusks" which either snaggle up out of the
mouth or curl back into the mouth, making eating nearly impossible.
Although some veterinarians will be willing to regularly trim the
teeth, this is stressful for the rabbit. Also, clipping the teeth
rather than filing or grinding them down can be dangerous, since
micro-fractures of the tooth from clipping can travel below the
gumline, inviting bacterial infection that can ultimately be
life-threatening.

Many rabbit expert vets believe that the best way to treat maloccluded incisors is to
extract them. This is a surgical
procedure that must be done very carefully and patiently by your
rabbit-experienced veterinarian, to ensure complete, permanent removal.
The rabbit will probably need to be on pain medication
for a day or two after surgery,
but once the patient has recovered, the only adjustment the rabbit
"parent" needs to make is to cut up fresh food into bite-sized pieces, since the cutting teeth (incisors) will be gone.
Pellets and hay can be handled as before, without problems.

Molar (Cheek Tooth) Problems

Many rabbits who have maloccluded incisors, and even many
who have perfectly aligned incisors still develop molar spurs. These
are sharp points on the edges of the molars that result from uneven
wear.
Spurs that form on the lower molar arcade point inwards towards the tongue, and are known as lingual ("tongue") spurs. Spurs that form on the upper arcade poke outwards into the cheek, and are called buccal ("mouth") spurs (Figure 1).

These points can stab and abrade the tongue and cheek.
Rabbits, being prey animals, do not readily show signs of pain. Your first sign of trouble might be something as subtle as a change in eating habits, and the nature of this change is unpredictable and idiosyncratic (unique to the individual).

In some extreme cases, molar spurs can actually grown into the tongue or cheek, causing extreme pain. There have been cases of a molar spur going undetected for so long that it formed a bridge over the tongue, preventing the bunny from eating properly.

Left unattended, the pain of dental disease can trigger a potentially life-threatening condition
known as ileus). Before this happens, you surely want to get your bunny to a rabbit-savvy vet for examination and treatment.

Dental Disease and Elder Buns

Dental disease can also develop as a rabbit ages. With advancing years, rabbits (like all of us) tend to lose bone density. When this happens in the already-delicate bones of the skull, the teeth can become ever-so-slightly looser in their sockets, and this can cause uneven wear.

Rabbit teeth do not have true roots, but the bases of the teeth can become infected when the teeth are loose, as bacteria from the mouth travel downwards along the gumlines. Swelling almost anywhere along the mandible (lower jaw) or maxilla (upper bones of mouth) can signal an infection that requires at least antibiotic treatment, and possibly surgical treatment.

The base of the rabbit tooth is the location of the constantly dividing tissue that gives rise to the teeth.
In some cases, the bases of the molars and/or incisors begin to extend farther into the jaw bone than normal (this is far more common in older
rabbits). These "rogue roots" may begin to impinge on the tear ducts,
causing epiphora (runny eyes). Sometimes, such "overgrown" molar bases may even puncture
the sinuses or the eye orbit, allowing intrusion of mouth bacteria into
areas meant to remain sterile. Abscesses can result.

If you have an elderly bunny with any signs of dental disease, ask your veterinarian to do a complete oral exam including head
radiographs to detect the extent of the problem and the appropriate course of treatment.

Treating Dental Disease

Molar spurs can be filed smooth by your veterinarian, who may use
anything from a Dremel tool to a blunt-tipped diamond file. The
procedure ordinarily requires anesthesia (e.g., isoflurane or sevoflurane gas),
but usually can be done relatively quickly.

If your bunny is showing any signs such as

Drooling

Runny eyes

Eagerly going to food, but then acting unwilling to actually take
it into the mouth

Gradual (or sudden) change in dietary habits (e.g., refusing to
eat pellets, but happy to eat hay--or the other way around!)

Unusual eating habits, such as a willingness to eat only one or two
food items, and rejecting other types.

excessive drinking (this also can be a sign of renal disease, but rabbits with sore mouths will sometimes drink constantly in an attempt to soothe a sore mouth)

then it's time to get him/her to a veterinarian who is very familiar
with rabbit dental disease. If your bunny does turn out to have dental problems, you'll be amazed at his relief once
the teeth are properly filed and in the right shape. Make a dental
check up a regular part of your bunny's well-bun exam!